WispStation 5 ethernet port damaged - suggestion

[zetanox]

I have installed 11 WISPSTATION5 in 3 different location.
3 point at City A
4 point in City B
4 Point in City C
In case A and C a have power supply of 20v + POE passive
In case B power supply is 18v + POE passive

After few week of great work (18-24Mbit) in a day 1 wispstation of City A and 2 unit ws5 of city B are dead in LAN PORT.

In wireless mode they response at ping and I can read web configuration, but in LAN they not response. Switch connected not blink led and I use to diagnose a PC that say "lan cable disconnected (cross red)".

I have read to solve a problem in LS5 (I think is the same) I can replace KENDIN KSZ8721B, not me but a great solder... -) I have counte 24 pin each side that means 48 dissolder and 48 solder of half millimeter... Gulp
If correct I will do in next day (I will order in European supply).
UBNT support please response me...

My ask is: Can I do to avoid next damaged in other board wispstation5 continue live?
You suggest to reduce power supply at 12v?
Can resolve with a "Filter"? If yes wich?
Why can damage simple remove and insert power supply?
Thank's

PS: all board have test date 18/08/08 and I had upload last firmware Ubiquiti Air OS v3.2 - WispStation5

[InoX]

use a surge arester

[doddel]

With only 4 ws5 units operational, 2 of them within a year lost lan connectivity after some bad weather and lightning in the area, but not really close.
Some 30 older units of another make in similar circumstances never had this problem. The ethernet connection of the wispstation board appears to be quite vulnerable to electrostatic discharge effects.
I managed to revive the units by replacing the KENDIN KSZ8721B integrateed circuit. (sourced from digi-key.com) but as other smd components are quite close this is only doable by the somewhat experienced with proper tools.
To remove the IC I used a soldering station with hot air nozzle and I protected the surroundings by a brass foil folded to form a shallow wall around the IC with flaps to the sides. To solder the new one I reversed the process and tipped all leads with a soldering iron with ultra fine tip.
Doable but not easy.

[gingerwolf]

The Kendin-Circuit is the Eth-Phy. If this gots broken, you might had some trouble on the ethernet-cable installation. Have you used shield cable, also additionaly grounded on its ends ? I've several Installations with UBNT-gear, also on top of a hill that catches lightning very easy. None of them had any Problems.

cheers gingerwolf